This Convertible Mountain Bike Helmet Sold Out in 2 Weeks

Sweet Protection launched the Arbitrator mountain bike helmet this spring in a limited run, and it promptly sold out.

Why? Because for $300, this helmet is so dialed that it functions as a certified full-face helmet and transitions to a well-ventilated trail riding helmet within seconds. I recently traveled to the brand’s Norway headquarters in Trysil to learn more about the brand and this revolutionary new helmet.

The Sweet Protection Arbitrator is slick. Rip downhill courses with a full-face, fully certified 980g (in M/L) helmet. Then, snap off the stout face cover to reveal a breezy 550g trail helmet to pedal uphill for enduro events. Or just wear the trail helmet as a daily rider and throw on the facemask for days in the downhill park.

This “one helmet for most rides” was the mission of Norway-based Sweet Protection. And from the looks of the model, the brand hit the helmet on the head — but it wasn’t easy.

I sat down and spoke with designer Ståle Norman Møller, director of design and development at Sweet Protection. He explained that the Arbitrator is the most complex engineering puzzle in the brand’s 20-year history.

Of the 87 parts in the new Sweet Protection Arbitrator helmet, the brand produces every one, except for a single screw, in-house. The helmet has tolerances as fine as 0.02 mm, and everything has to be certified across multiple standards and countries.

Sweet Protection Arbitrator MIPS Helmet

The Arbitrator starts with a four-piece shell with a Zytel frame. A carbon fiber chin guard adds strength in critical areas. I tried to crush the ring-shaped chin guard’s carbon fiber inlay in my hands, and it barely budged.

The meat of the head protection comes in an EPS foam liner. Sweet Protection then adds a MIPS system to reduce force from rotational impacts.

It ventilates the helmet through digitally optimized airflow channels, including one that channels air to cool the superficial temporal artery.

While I didn’t get to ride with the helmet (it’s in high demand), I was really impressed when examining it in the office.

The chin guard attaches quickly but requires a lot of force to lock and unlock from the main helmet. It does feel extremely secure, and the parts fit together nearly perfectly.

Overall, this is a really slick helmet that should be on the top of the list for enduro mountain bikers and others who want a do-all trail and downhill helmet. It should give you the freedom, low weight, and ventilation you need on the uphill, and then easily transform to give the protection you require when ripping back down.

For those interested in picking one up, a few online retailers have limited sizes available. Sweet Protection expects to release a second batch in July.